package evm

import (
	"math/big"

	abci "github.com/tendermint/tendermint/abci/types"

	sdk "github.com/cosmos/cosmos-sdk/types"

	ethtypes "github.com/ethereum/go-ethereum/core/types"
)

// BeginBlock sets the block hash -> block height map and resets the Bloom filter and
// the transaction count to 0.
func BeginBlock(k Keeper, ctx sdk.Context, req abci.RequestBeginBlock) {
	if req.Header.LastBlockId.GetHash() == nil || req.Header.GetHeight() < 1 {
		return
	}

	k.SetBlockHash(ctx, req.Header.LastBlockId.GetHash(), req.Header.GetHeight()-1)

	// reset counters
	k.Bloom = big.NewInt(0)
	k.TxCount = 0
}

// EndBlock updates the accounts and commits states objects to the KV Store.
//
func EndBlock(k Keeper, ctx sdk.Context, req abci.RequestEndBlock) []abci.ValidatorUpdate {
	// Gas costs are handled within msg handler so costs should be ignored
	ctx = ctx.WithBlockGasMeter(sdk.NewInfiniteGasMeter())

	// Update account balances before committing other parts of state
	k.UpdateAccounts(ctx)

	// Commit state objects to KV store
	_, err := k.Commit(ctx, true)
	if err != nil {
		panic(err)
	}

	// Clear accounts cache after account data has been committed
	k.ClearStateObjects(ctx)

	bloom := ethtypes.BytesToBloom(k.Bloom.Bytes())
	k.SetBlockBloom(ctx, ctx.BlockHeight(), bloom)

	return []abci.ValidatorUpdate{}
}